feat(skill/playwright): unify shared-session CLI flow for web skills

skills/xiaohongshu-engage/SKILL.md

@@ -13,6 +13,13 @@ description: "Browse XiaoHongShu (小红书) with Playwright and execute account
 4. Validate action success from UI state.
 5. Summarize exactly what was done.
 
+## Shared Session Policy
+
+- Reuse a single Playwright CLI session across all web-automation skills:
+  - `export PLAYWRIGHT_SHARED_SESSION=codex-shared`
+- Use `/Users/xd/java/xhs/tools/pw` as the only Playwright CLI entrypoint.
+- Do not pass `--session` directly in skill-specific commands.
+
 ## 1) Confirm Login State
 
 - Snapshot current page.

skills/xiaohongshu-engage/agents/openai.yaml

@@ -1,7 +1,7 @@
 interface:
   display_name: "XHS Engage"
   short_description: "Browse feed and engage via likes, favorites, and comments."
-  default_prompt: "Use $xiaohongshu-engage to browse XiaoHongShu and interact with relevant posts through likes, favorites, and concise comments."
+  default_prompt: "Use $xiaohongshu-engage with PLAYWRIGHT_SHARED_SESSION=codex-shared and execute browser steps only through /Users/xd/java/xhs/tools/pw while browsing XiaoHongShu and interacting with relevant posts through likes, favorites, and concise comments."
 
 policy:
   allow_implicit_invocation: true